The United Nations human rights office said Tuesday that it will stop updating its death toll for the civil war in Syria, with information becoming harder to verify after the bloody conflict has dragged on for almost three years.

The human rights office also said it could no longer verify its July figure of 100,000 dead, the Associated Press reports.

“It was always a very difficult figure,” spokesman Rupert Colville said. “It was always very close to the edge in terms of how much we could guarantee the source material was accurate. And it reached a point where we felt we could no longer cross that line. So for the time being, we’re not updating those figures.”

Since the UN doesn’t have full access to Syria, the organization says that it is unable to verify source material on deaths. While the death toll numbers used to be provided by various nongovernmental organizations in Syria, over the last year that number has decreased to two or three.